AtCYP20-2 is an auxiliary protein of the chloroplast NAD(P)H dehydrogenase complex

Abstract 

AtCYP20-2 is one of 16 immunophilins in thylakoid lumen. The presence of the isomerase domain in AtCYP20-2, an enrichment of AtCYP20-2 in the stroma membranes and it’s co-migration with NAD(P)H dehydrogenase (NDH) in native gels provide evidence that AtCYP20-2 is an auxiliary protein of NDH. When different NDH mutants were studied, AtCYP20-2 was found to be strongly reduced especially in mutants deficient in the membrane domain of NDH, thus suggesting a role in the assembly of NDH hydrophobic domain. Lack of AtCYP20-2, however, did not lead to severe malfunction of NDH, indicating redundancy in the function of lumenal immunophilins.

Abbreviations: Arabidopsis, Arabidopsis thaliana, BN-PAGE, blue native gel, cyt, cytochrome, F₀-rise, post-illumination rise in chl fluorescence, FKBP, FK506 binding protein, LHC, light harvesting complex, NDH, NAD(P)H dehydrogenase, PPIase, peptidyl prolyl isomerase, PS, photosystem

Keywords: NAD(P)H dehydrogenase, Immunophilin, Thylakoid lumen